1. Field of the Invention
The present invention relates to a headlight beam control system and a headlight beam control method.
2. Description of the Related Art
A conventional navigation apparatus detects the current position of a vehicle using a GPS (Global Positioning System) sensor and determines the direction of the vehicle based on the angle of traverse of the vehicle as detected by a gyroscopic sensor. Map data is read from a data storage unit, and a map screen is shown on a display unit of the navigation apparatus. A map of an area including the current position of the vehicle is displayed on the map screen, and a mark is displayed on the map to indicate the current position and direction of the vehicle. A driver is thereby assisted in driving his/her vehicle in accordance with the current position and direction of the vehicle displayed on the map.
When the driver inputs a destination and specifies a search condition, the map data is searched in accordance with the specified search condition to find a route from the current position to the destination. If a route is found, it is displayed on the map screen together with the map indicating the position of the vehicle, and route guidance along the found route is provided. Thus, the driver is able to follow the displayed route.
When a vehicle is driven at nighttime, if there is a leading vehicle running ahead of the first vehicle, high beam headlights of the first vehicle can influence driving of the leading vehicle. To avoid such a problem, it is known to provide a headlight beam control system to control the headlight beams by adjusting the optical axes of the headlights in accordance with the distance between the first vehicle and leading vehicle. See for example, Japanese Unexamined Patent Application Publication (Kokai) No. 6-84099.
In the conventional headlight beam control system, an image of a leading vehicle is taken using a front view camera, the leading vehicle is recognized based on image data generated from the captured image, and the headlight beams are controlled by adjusting the optical axes of the headlights in accordance with the distance to the recognized leading vehicle.
Therefore, in a case where a vehicle passes the user's vehicle, the passing vehicle is recognized as a leading vehicle only after the passing vehicle reaches a position in front of the user's vehicle. This delay in controlling the headlight beams is undesirable.